This project has been undertaken to study various aspects of cell locomotion and chemotaxis. A mathematical theory has been devised to relate chemotropism indices to the characteristic random walks of individual cells. Analytical expressions to quantitate capillary migration (MIF) assays have been derived. New procedures for measuring macroscopic coefficients of cell migration are being developed. BIBLIOGRAPHIC REFERENCES: Nossal, R., and Chang, Y.T.: A procedure for determining mobility parameters for cells moving along surfaces. J. Mechanochem. Cell Mot. 3, 247-251 (1976). Nossal, R.: Mathematical analysis of a capillary migration assay for cellular immune sensitivity. J. Theoret. Biol. 64 703-722 (1977).